linux-2.6.33/do_page_fault()(arm) の履歴(No.2)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-2.6.33/do_page_fault()(arm) へ行く。
  • 1 (2010-12-28 (火) 10:01:41)
  • 2 (2010-12-28 (火) 11:33:38)

---

参照元†

• linux-2.6.33/do_page_fault()

説明†

• パス: linux-2.6.33/arch/arm/mm/fault.c

• FIXME: これは何？
  • 説明

引数†

返り値†

参考†

実装†

MMU 有効の場合†

#ifdef CONFIG_MMU
（略）

static int __kprobes
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	int fault, sig, code;

• • linux-2.6.33/task_struct

• linux-2.6.33/mm_struct

	if (notify_page_fault(regs, fsr))
		return 0;

• • linux-2.6.33/notify_page_fault()

	tsk = current;
	mm  = tsk->mm;

• • linux-2.6.33/current(global)

	/*
	 * If we're in an interrupt or have no user
	 * context, we must not take the fault..
	 */
	if (in_atomic() || !mm)
		goto no_context;

• • linux-2.6.33/in_atomic()

	/*
	 * As per x86, we may deadlock here.  However, since the kernel only
	 * validly references user space from well defined areas of the code,
	 * we can bug out early if this is from code which shouldn't.
	 */
	if (!down_read_trylock(&mm->mmap_sem)) {
		if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
			goto no_context;
		down_read(&mm->mmap_sem);

• • linux-2.6.33/down_read_trylock()

• linux-2.6.33/user_mode()

• • linux-2.6.33/search_exception_tables()

• linux-2.6.33/down_read()

	} else {
		/*
		 * The above down_read_trylock() might have succeeded in
		 * which case, we'll have missed the might_sleep() from
		 * down_read()
		 */
		might_sleep();

• • linux-2.6.33/might_sleep()

#ifdef CONFIG_DEBUG_VM

• • linux-2.6.33/CONFIG_DEBUG_VM

		if (!user_mode(regs) &&
		    !search_exception_tables(regs->ARM_pc))
			goto no_context;
#endif
	}

	fault = __do_page_fault(mm, addr, fsr, tsk);
	up_read(&mm->mmap_sem);

• • linux-2.6.33/__do_page_fault()

• linux-2.6.33/up_read()

	/*
	 * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
	 */
	if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
		return 0;

• • linux-2.6.33/likely()

• linux-2.6.33/VM_FAULT_ERROR

• • linux-2.6.33/VM_FAULT_BADMAP

• linux-2.6.33/VM_FAULT_BADACCESS

	if (fault & VM_FAULT_OOM) {
		/*
		 * We ran out of memory, call the OOM killer, and return to
		 * userspace (which will retry the fault, or kill us if we
		 * got oom-killed)
		 */
		pagefault_out_of_memory();
		return 0;

• • linux-2.6.33/VM_FAULT_OOM

• linux-2.6.33/pagefault_out_of_memory()

	}

	/*
	 * If we are in kernel mode at this point, we
	 * have no context to handle this fault with.
	 */
	if (!user_mode(regs))
		goto no_context;

	if (fault & VM_FAULT_SIGBUS) {

• • linux-2.6.33/VM_FAULT_SIGBUS

		/*
		 * We had some memory, but were unable to
		 * successfully fix up this page fault.
		 */
		sig = SIGBUS;
		code = BUS_ADRERR;

• • linux-2.6.33/SIGBUS

• linux-2.6.33/BUS_ADRERR

	} else {
		/*
		 * Something tried to access memory that
		 * isn't in our memory map..
		 */
		sig = SIGSEGV;
		code = fault == VM_FAULT_BADACCESS ?
			SEGV_ACCERR : SEGV_MAPERR;

• • linux-2.6.33/SIGSEGV

• linux-2.6.33/VM_FAULT_BADACCESS

• • linux-2.6.33/SEGV_ACCERR

• linux-2.6.33/SEGV_MAPERR

	}

	__do_user_fault(tsk, addr, fsr, sig, code, regs);
	return 0;

• • linux-2.6.33/__do_user_fault()

no_context:
	__do_kernel_fault(mm, addr, fsr, regs);
	return 0;

• • linux-2.6.33/__do_kernel_fault()

}

MMU 有効の場合†

#else					/* CONFIG_MMU */
static int
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	return 0;

• 何もせず成功を返す。

}
#endif					/* CONFIG_MMU */

コメント†